Dietary, physical activity, and lifestyle behaviors of rural African American South Carolina children.

Overweight and obese children continue to be a growing problem, and differences exist, especially among racial and ethnic groups. Even though a poor diet and lack of physical activity are attributable factors to being overweight among children, indications exists that geographic location may also be important. In rural areas in the United States, childhood obesity is often higher than the national average. This study analyzed dietary, physical, activity, and lifestyle behaviors of rural African American children and their risk for becoming overweight. This study is a cross-sectional convenience sample of 98 students from a rural county in South Carolina in 2002. Findings showed rural female children were significantly more likely than rural male children to engage in physical activity for at least 20 minutes per day (odds ratio, 5.57; p = .0056). Given the increase in the prevalence of obesity especially among minority populations, the need exists to develop culturally appropriate nutrition and exercise interventions to assistchildren in a healthy weight loss attempt. Increased prevalence of obesity and other diseases among African Americans warrants aggressive interventions to reduce risk factors in this vulnerable population.

Development of the Soldier Health Promotion to Examine and Reduce Health Disparities (SHPERHD) Project Coordinating Center: challenges and opportunities within a university/community partnership.

The Soldier Health Promotion to Examine and Reduce Health Disparities (SHPERHD) Project was designed to be a partnership between the Institute for Partnerships to Eliminate Health Disparities at the University of South Carolina and the Fort Jackson United States Army Base located in Columbia, South Carolina. SHPERHD Project researchers are studying problems related to obesity and weight management, musculoskeletal injuries and infection, and mental health issues during recruitment, basic training, and post-deployment. In order to successfully develop targeted interventions to prevent and lower the incidence of injury, promote healthy nutrition, and decrease mental health issues, at the same time also reducing disparity gaps, the SHPERHD Project comprises a professional, technical, and administrative staff with specific competence in the operation of a Coordinating Center to handle the wide variety of areas related to military studies. This article discusses the procedures and processes that were implemented in the development of the SHPERHD Project Coordinating Center.

A high frequency of mtDNA polymorphisms in HeLa cell sublines.

The complete mtDNA sequences from the uncloned "founder" HeLa cells and from five sublines have been determined. These sequences all carry a common "core" of 38 single basepair alterations relative to the revised Cambridge Reference Sequence (CRS). The HeLa mitochondrial genome is of African descent and it is a member of the African L3 haplogroup. The sequence of the HeLa mtDNA resolves the uncertainty surrounding the mosaic composition of the original CRS for human mtDNA. Most importantly, we detected a total of eight polymorphisms that have arisen in the mtDNA coding region of different HeLa sublines. These observations suggest that HeLa mtDNA has a high rate of sequence divergence, relative to the phylogenetically-derived divergence rate for mtDNAs in the human population, which results from a relaxation of negative selection against the fixation of deleterious mutations. Furthermore, this high frequency of polymorphisms in HeLa mtDNA may reflect a process similar to the accumulation of somatic mtDNA mutations in human cancers. Preliminary analysis of single-cell derived subclone lines revealed the occurrence of another polymorphism and provided evidence for a large number of mtDNA segregation units.

Does the mitochondrial genome play a role in the etiology of Alzheimer's disease?

We report here the analyses of complete mtDNA coding region sequences from more than 270 Alzheimer's disease (AD) patients and normal controls to determine if inherited mtDNA mutations contribute to the etiology of AD. The AD patients and normal individuals were carefully screened and drawn from two populations of European descent in an effort to avoid spurious effects due to local population anomalies. Overall, there were no significant haplogroup associations in the combined AD and normal control sequence sets. Reduced median network analysis revealed that the AD mtDNA sequences contained a higher number of substitutions in tRNA genes, and that there was an elevated frequency of replacement substitutions in the complex I genes of the control sequences. Analysis of the replacement substitutions indicated that those arising in the AD mtDNAs were no more deleterious, on average, than those in the control mtDNAs. The only evidence for the synergistic action of mutations was the presence of both a rare non-conservative replacement substitution and a tRNA mutation in 2 AD mtDNAs, from a total of 145, whereas such a combination of mutations was not observed in the control sequences. Overall, the results reported here indicate that pathogenic inherited mtDNA mutations do not constitute a major etiological factor in sporadic AD. At most, a small proportion of AD patients carry a pathogenic mtDNA mutation and a small proportion of cognitively normal aged individuals carry a mtDNA mutation that reduces the risk of AD.

Sequence analysis of the mitochondrial genomes from Dutch pedigrees with Leber hereditary optic neuropathy.

The complete mitochondrial DNA (mtDNA) sequences for 63 Dutch pedigrees with Leber hereditary optic neuropathy (LHON) were determined, 56 of which carried one of the classic LHON mutations at nucleotide (nt) 3460, 11778, or 14484. Analysis of these sequences indicated that there were several instances in which the mtDNAs were either identical or related by descent. The most striking example was a haplogroup J mtDNA that carried the 14484 LHON mutation. Four different but related mitochondrial genotypes were identified in seven of the Dutch pedigrees with LHON, including six of those described by van Senus. The control region of the founder sequence for these Dutch pedigrees with LHON matches the control-region sequence that Macmillan and colleagues identified in the founder mtDNA of French Canadian pedigrees with LHON. In addition, we obtained a perfect match between the Dutch 14484 founder sequence and the complete mtDNA sequences of two Canadian pedigrees with LHON. Those results indicate that these Dutch and French Canadian 14484 pedigrees with LHON share a common ancestor, that the single origin of the 14484 mutation in this megalineage occurred before the year 1600, and that there is a 14484/haplogroup J founder effect. We estimate that this lineage--including the 14484 LHON mutation--arose 900-1,800 years ago. Overall, the phylogenetic analyses of these mtDNA sequences conservatively indicate that a LHON mutation has arisen at least 42 times in the Dutch population. Finally, analysis of the mtDNA sequences from those pedigrees that did not carry classic LHON mutations suggested candidate pathogenic mutations at nts 9804, 13051, and 14325.

Reduced-median-network analysis of complete mitochondrial DNA coding-region sequences for the major African, Asian, and European haplogroups.

The evolution of the human mitochondrial genome is characterized by the emergence of ethnically distinct lineages or haplogroups. Nine European, seven Asian (including Native American), and three African mitochondrial DNA (mtDNA) haplogroups have been identified previously on the basis of the presence or absence of a relatively small number of restriction-enzyme recognition sites or on the basis of nucleotide sequences of the D-loop region. We have used reduced-median-network approaches to analyze 560 complete European, Asian, and African mtDNA coding-region sequences from unrelated individuals to develop a more complete understanding of sequence diversity both within and between haplogroups. A total of 497 haplogroup-associated polymorphisms were identified, 323 (65%) of which were associated with one haplogroup and 174 (35%) of which were associated with two or more haplogroups. Approximately one-half of these polymorphisms are reported for the first time here. Our results confirm and substantially extend the phylogenetic relationships among mitochondrial genomes described elsewhere from the major human ethnic groups. Another important result is that there were numerous instances both of parallel mutations at the same site and of reversion (i.e., homoplasy). It is likely that homoplasy in the coding region will confound evolutionary analysis of small sequence sets. By a linkage-disequilibrium approach, additional evidence for the absence of human mtDNA recombination is presented here.